1. We produce transgenic mice which express human class 1 major histocompatibility complex (MHC) gene, HLA-A2 and HLA-B7, by egg microinjection techniques. 2. We study gene integration and gene expression in such transgenic mice by Southern and Northern blot hybridization, immunological assays and two-dimensional protein gel analysis. The inheritance of the human HLA gene is also studied. 3. We study the function of HLA antigens in the transgenic mice. We generate cytotoxic T cell responses using human influenza virus, H-Y antigen and dinitrophenyl haptens in transgenic mice and determine the pattern of restriction specificity. 4. We study the tolerance against the HLA antigens in transgenic mice in skin graft, mixed lymphocyte reaction (MLR) and cytotoxic T cell responses.